Most sugars are highly soluble in water, but not all solid organic compounds can be dissolved in water with reasonable solubility. It is highly desirable to dissolve many solid organic compounds in water, or to disperse solid organic compounds into water to form a stable hydrocolloid. It would be most beneficial to create a method that was applicable to the widest variety of organic solids. Curcumin, 1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione, is a natural yellow-orange dye extracted from the rhizomes of Curcuma longa L. and it has a variety of biological activities and pharmacological actions. Unfortunately, curcumin is not water soluble and that limits its' effective bioavailability in many systems. Many attempts have been made to disperse curcumin into water to improve its bioavailability. A self-microemulsifying drug delivery system comprising a microemulsion of curcumin with oils and surfactants was reported to improve the solubility of curcumin in water. Jing Cui, Bo Yu, Yu Zhao, Weiwei Zhu, Houli Li, Hongxiang Lou, Guangxi Zhai, “Enhancement of oral absorption of curcumin by self-microemulsifying drug delivery systems”, International Journal of Pharmaceutics Vol. 371, 148-155, 2009. A curcumin-phospholipid complex was reported to greatly increase both the bioavailability and the formation of metabolites as compared to unformulated curcumin. T. H. Marczylo, R. D. Verschoyle, D. N. Cooke, P. Morazzoni, W. P. Steward, A. J. Gescher, “Comparison of systemic availability of curcumin with that of curcumin formulated with phosphatidylcholine”, Cancer Chemother. Pharmacol., Vol. 60, 171-177, 2007. A polymeric nanoparticle-encapsulated curcumin, nicknamed “nanocurcumin”, was also reported as a novel strategy to improve the bioavailability of curcumin. S. Bisht, G. Feldmann, S. Soni, R. Ravi, C. Karikar, A. Maitra and A. Maitra, “Polymeric nanoparticle-encapsulated curcumin (“nanocurcumin”): a novel strategy for human cancer therapy”, Journal of Nanobiotechnology, Vol. 5:3, 2007. All of these methods involve using other chemical compounds in addition to the desired organic compound, in these references curcumin, to form a complex having improved bioavailability and solubility in water.
Pulsed laser ablation of metal or metal-alloy targets in liquids is one of the physical methods used to produce metal and metal-alloy nanoparticles. In this process, a pulsed laser beam is focused on the surface of a target that is submerged in a liquid. The ablated material re-nucleates in the liquid and forms nanoparticles. In recent years, there have been reports of applying pulsed laser ablation techniques to very small volumes of organic nanoparticle preparations in which organic microcrystalline powders suspended in a poor solvent are irradiated with intense laser pulses, which induce fragmentation of the initial crystals. See for example, Yoshiaki Tamaki, Tsuyoshi Asahi, and Hiroshi Masuhara, “Tailoring nanoparticles of aromatic and dye molecules by excimer laser irradiation”, Applied Surface Science, Vol. 168, 85-88, 2000; Teruki Sugiyama, Tsuyoshi Asahi, and Hiroshi Masuhar, “Formation of 10 nm-sized Oxo(phtalocyaninato)vanadium(IV) Particles by Femtosecond Laser Ablation in Water”, Chemistry Letters Vol. 33, No. 6, 724, 2004; and T. Asahi, T. Sugiyama, and H. Masuhara, “Laser Fabrication and Spectroscopy of Organic Nanoparticles”, Accounts of Chemical Research, Vol. 41, No. 12, 2008. A poor solvent is a liquid that the target organic material has low to no solubility in. After a sufficient amount of exposure to the laser beam, the opaque suspension of organic microcrystalline powders is converted into a transparent colloidal suspension. This laser ablation approach appears to convert organic microcrystalline powders directly into stable nanocolloidal suspensions without additives and chemicals. All of the results reported to date have been conducted in a cuvette with a total volume of 3 milliliters, and it is difficult to scale up from this small volume to mass production of organic nanoparticles with this laser ablation approach. Obviously, the pulsed laser ablation of an organic microcrystalline powder suspension in a fixed volume small cuvette cannot maintain a constant efficiency of generation of organic nanoparticles because of the decreasing amount of microcrystalline powder available during the ablation process. Similar results were also reported by several other groups, see for example I. Elaboudi, S. Lazare, C. Belin, D. Talaga. And C. Labrugère, “From polymer films to organic nanoparticles suspensions by means of excimer laser ablation in water”, Appl. Phys. A, Vol 93, 827-831, 2008 and R. Yasukuni, M. Sliwa, J. Hofkens, F. C. De Schryver, A. Herrmann, K. Mullen, and T. Asahi, “Size-Dependent Optical Properties of Dendronized Perylenediimide Nanoparticle Prepared by Laser Ablation in Water”, Japanese Journal of Applied Physics, Vol. 48, 065002, 2009.
It is desirable to develop a method for formation of nanoparticles from organic compounds that are poorly soluble in water and other liquids to increase their bioavailability and usefulness in biological systems. In addition, it would be useful to develop a production method for organic nanoparticles that avoids coagulation, eliminates any requirement for a stabilizing agent, and that provides for rapid throughput and scale up to mass production levels.